$0 = Twitter’s internal revenue projection for first half of 2009, according to internal forecast leaked to TechCrunch. (*2)

Footnotes:

*1 TechCrunch article based on leaked Twitter corporate documents it says were sent to it this week by a hacker. The blog’s publisher, Michael Arrington, notes that membership figures and other assumptions are already out of date:

Twitter has told us that this was never an official document and it certainly is no longer accurate. But it gives an interesting glimpse into the company’s financial targets nonetheless.

Twitter confirmed some corporate documents were lost after an administrative employee’s account was hacked. It has not confirmed any leaked details.

*3 37.3 mln users worldwide – ComScore data May 2009. This includes 16 million U.s. users. Using different measurement methods, Compete.com estimated that Twitter had 23 million U.S. users in June.

*4 A poll for the All Things D conference in May found 51 percent of U.S. Twitter users sign on less than once a month. Since comScore data only counts visitors older than 15 years old on a monthly basis, one can extrapolate that the 37.3 figure represents only the 49 percent of active users. The 75 million estimate combines active and inactive members who have signed up for an account but rarely or never visit Twitter. The poll surveyed 1,005 members of the U.S. general public and was conducted by by Penn, Schoen & Berland Associates.

At the same time there is a small contingent of users who are very active. Specifically, the top 10% of prolific Twitter users accounted for over 90% of tweets. On a typical online social network, the top 10% of users account for 30% of all production … The pattern of contributions on Twitter is more concentrated among the few top users than is the case on Wikipedia, even though Wikipedia is clearly not a communications tool. This implies that Twitter’s resembles more of a one-way, one-to-many publishing service more than a two-way, peer-to-peer communication network.